In the field of communications, compared with a traditional Long Term Evolution (LTE) system, if a higher carrier frequency is adopted for transmission in mobile communications, an average path loss may be much larger than that of the traditional LTE system. For example, when a carrier frequency of 28 GHz is adopted for transmission, a path loss is calculated by utilizing Formula (1):
                              L          f                =                              (                                          4                ⁢                                                                  ⁢                π                ⁢                                                                  ⁢                R                            λ                        )                    2                                    (        1        )            
where, R is a radius of cell coverage, and λ is a wavelength of a corresponding carrier.
Information of an average ratio of a high-frequency path loss value to an LTE path loss value is calculated as follows.
                                          L            H                    /                      L            L                          =                                                            (                                                      4                    ⁢                                                                                  ⁢                    π                    ⁢                                                                                  ⁢                    R                                                        λ                    H                                                  )                            2                        /                                          (                                                      4                    ⁢                                                                                  ⁢                    π                    ⁢                                                                                  ⁢                    R                                                        λ                    L                                                  )                            2                                =                                                    (                                                      λ                    L                                                        λ                    H                                                  )                            2                        ≈            100                                              (        2        )            
where, LH is a high-frequency path loss, and LL is a low-frequency path loss.
In high-frequency communications, in order to ensure coverage, i.e., to ensure that a receiving side meets a minimum Signal to Interference plus Noise Ratio (SINR) requirement, it may be needed to increase gains of a transmitter and a receiver.
                              P          r                =                                            P              t                        ⁢                          G              t                        ⁢                                                            G                  r                                ⁡                                  (                                      λ                                          4                      ⁢                                                                                          ⁢                      π                      ⁢                                                                                          ⁢                      R                                                        )                                            2                                =                                    P              t                        ⁢                          G              t                        ⁢                                          G                r                            /                              L                f                                                                        (        3        )            
where, Pr is receiving power, Pt is transmitting power, Gt is a transmitting antenna gain, and Gr is a receiving antenna gain.
LTE communications require a maximum coverage for 100 km. If an average path loss (open area) is only taken into consideration according to maximum coverage, high-frequency communications may maximally achieve a coverage area for 1 km. If the characteristics of air absorption (oxygen absorption, carbon dioxide, etc.), rain fading, shadow fading sensitivity, etc. of actual high-frequency carriers are taken into consideration, coverage capable of being actually supported may be less than 1 km.
If the high-frequency communications support maximum coverage for 1 km, compared with the LTE system, SINRs that can be achieved under the same coverage area are different. For example, the SINR of high-frequency communications is less than the SINR of the LTE system by at least 20 dB. In order to ensure that the high-frequency communications and the LTE system have similar SINRs within a coverage range, it may be needed to ensure antenna gains of the high-frequency communications. As the high-frequency communications have a shorter wavelength, more antenna elements may be accommodated in unit area, and more antenna elements may provide higher antenna gains, thus ensuring the coverage performance of the high-frequency communications.
In the field of communications, a second communication node serving as a transmitting end may transmit a plurality of uplink access signals to a first communication node serving as a receiving end. However, in view of a current technology, the first communication node cannot learn of whether the received uplink access signals come from the same second communication node, thus increasing overheads of an access process to result in that the first communication node cannot respond to more uplink accesses.
Any effective solution has not been proposed yet at present for the problem in the field of communications where the first communication node cannot respond to more uplink accesses.